For me it all depends on the "NAT"
I'm not sure if it is the same on PS3, but im sure Goat could fill in the rest, & help you & your clan to make sure they are set up best to connect to each other.
For me i know riught away if we cant connect, i have to log off go test my connection & most of the time the "NAT" will say Moderate or Strict, which means i need to reset my router, then when i test it again it says Open which means if there are any issues connecting it isn't me. ;D
So then we move on to the next guy who is having trouble or is in the room that needs to log out & check his "NAT" and so on..
IF everyone's "NAT" is open there is never a problem, so im guessing it is you or one of your clanmates' NAT that is causing the problem.
That is my cliff notes version, but like i said let Goat help you out with more details & possibly a PS3 senario.